Growing Lavandula Grosso: Soil, Pruning, and Reblooming Tips

Lavandula 'Grosso' is a popular lavandin cultivar prized for its long stems and intense fragrance. A gardener in coastal California reported high failure rates with English lavenders like 'Grosso', 'Provence', and 'Munstead' despite well-drained silty soil. The key to success lies in soil amendment and disciplined pruning.

Soil Requirements

Lavenders thrive in alkaline conditions. Add 1 cup of powdered lime per established plant annually, worked into the soil within the plant's drip line. Granular lime is also acceptable. This raises pH and improves nutrient availability.

Pruning Schedule

Prune every 3 weeks during summer and early fall. Shear back new growth by one-third to encourage bushy, vigorous plants. Regular pruning prevents woody centers and promotes fresh foliage.

Reblooming Potential

'Grosso' typically blooms once in early summer. While pruning after flowering may stimulate a light second flush, it's not guaranteed. For testing, try pruning one or two plants on schedule and observe. Avoid heavy pruning during peak bloom if you want to enjoy the flowers.

Additional Tips

• Ensure excellent drainage—lavenders hate wet feet.
• Full sun is non-negotiable (6+ hours daily).
• Use organic fertilizer like liquid fish/seaweed every 3 weeks during active growth.

With lime-amended soil, consistent pruning, and proper drainage, 'Grosso' can thrive even in challenging coastal climates.